Moray Eels: Nocturnal Hunters of the Hawaiian Reef
During the day fish swim and forage, their bright colors admired by snorkelers and divers. As twilight approaches, night critters emerge from their burrows and coral polyps open their delicate tentacles to feed on plankton. The reef comes truly alive at night. This is the domain of the moray eel slithering down a lava rock ledge to disappear in a dark cave.
Long feared and respected, eels evoke visions of serpents waiting to pounce on unsuspecting humans. In ancient Rome, the emperor Nero was said to punish disobedient servants by throwing them
into pits of hungry eels. In modern times, Mike Nelson, of the 1960s series Seahunt, had frequent encounters with eels and fought them off with his trusty dive knife. Movies like The Deep portray the moray eel as a creature to be feared. Yet contrary to these images, eels are not vicious man-eaters, but fascinating reef fish with an odd appearance.
Moray eels, or puhi in Hawaiian, are very abundant in island waters. Represented by 40 species in the family Muraenidae, they are quite diverse in size, appearance and habits, but there are only a few eels that are unique to the islands. This is due to their long larval stage during which they drift in ocean currents through- out the Pacific. The Giant Moray can reach a length of 10 feet and weigh 75 pounds. Imagine coming face to face with this creature, the vision appearing even 25% larger due to refraction from a mask!
Photo by Julie Gardener, cleaner shrimp working on the morays teeth!
Lacking scales and protruding fins, it is easy to think of eels as a separate category, but they are truly bony fishes. In the moray, the dorsal, caudal and anal fins are all fused, and instead of scales, nature has provided them with a layer of mucus which protects the skin from germs and parasites. Perfectly adapted for the reef, the moray are efficient hunters. They have poor eyesight but a keen sense of smell. They hunt at night, locating resting prey such as damselfish or cardinal-fish.
One inhabitant of the reef that outsmarts the moray is the parrotfish, which sleeps in a gelatinous cocoon that hides its smell. Octopus and moray are enemies. Both dwell in similar areas and hunt as ambush predators. Although the octopus is intelligent, this competition usually ends with the eel as the victor. His powerful jaws will clamp onto the soft body of the octopus, eating one tentacle at a time. If the octopus is lucky he will escape with some tentacles left; the I missing ones will grow back.
During the day, moray eels can be seen poking opening and closing their mouths, their rows of back- their heads out of the reef, ward pointing teeth looking menacing. This is not a sign of hunger or aggression, but the way these creatures breathe, pumping water over gills which are located behind the jaw. The teeth ensure that a slippery fish will have a one-way journey to the stomach! Some of the have teeth but grinding plates for crushing crabs, morays, such as the Snowflake and Zebra eels, don't urchins and other invertebrates. Like most predators with big appetites, this family will "luau" and then rest for a few days.
It is best not to stick your hands into holes and crevices while snorkeling and diving. An eel will defend its territory and can inflict painful bites. Some dive masters feed eels, making them "tame," but since an eel's eyesight is poor, this is unwise. The animals cannot dis- cern fingers from squid! It's better to just observe reef animals in the wild instead of attempting to change their behavior.
Popular in Europe, Japan and China as a culinary delight, moray eels are raised for food. Thousands of tons are caught each year to the delight of the fisheries industry.
With your new understanding of these curious animals, you will be able to exclaim to your buddy, "That's a Moray!" without fear.
